Western Ragweed

Scientific Name:

Ambrosia psilostachya


Herbaceous Plant


Distrubed sites, dry rangelands, and hillsides


North America


No listed status

This species is


to the Truckee Meadows.


Western ragweed has tall leaves that are greenish-gray in color. The leaves are hairy and grow to between 2 and 5 inches in length. Western ragweed seed pods, which sit on top of the plants' long centralized stems, grow to between 2 and 6 inches in length. The seeds resemble a grain husk and become bristly and pointed with age.

Fast Facts:

  • Western ragweed can reproduce through rhizomes, which means it can “shoot” out new plants from the original plant’s root system. Therefore, they often have long root systems.

  • This plant is native to North America and is known for its contribution to fall hay fever. The pollen produced by the western ragweed can be very irritating to people.

  • The stems and leaves of western ragweed have been used by the Kumeyaay people to treat dandruff. The stems and leaves were crushed into a mash.



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